Case Studies of Seismic Nonstructural Retrofitting in
School Facilities
December 2005
Educational Facilities Research Center, National Institute for Educational Policy Research,
Study Group Report on the "Investigative Research for Promoting the Seismic
Retrofitting of School Facilities"
学校施設の質的改善を伴う耐震改修マニュアル
Case Studies of Seismic Nonstructural Retrofitting in School Facilities
Contents
1. Introduction
2. Definition of Nonstructural Members
3. Case studies of seismic retrofitting
Cases of Seismic Nonstructural Retrofitting
1) Ceiling material
2) Window and windowpane
3) Exterior wall and siding (concrete block, ALC, etc.)
4) Lighting fixture
5) Outdoor unit (air conditioner and heating unit)
6) Elevated water tank and cooling tower
7) Chimney
8) Refrigerator
9) Bookshelf and locker
10) TV and computer
11) Piano
12) Machine tool
13) Storage shelves in special classes
14) Equipment and facilities in gymnasiums
15) Shoe locker
16) Walls and gateposts
17) External staircase and surroundings
18) Retaining walls
19) Other items
Reference 1
Bibliography
Reference 2
Investigative Research for Promoting the Seismic Retrofitting of School Facilities (Purpose of the
Study Group)
Case Studies of Seismic Nonstructural Retrofitting in School Facilities
1. Introduction
Securing the safety of school facilities against earthquakes is important, because children spend a
large part of the day studying and playing at schools, which also act as emergency evacuation facilities for the
local community.
This document is intended for local authorities that establish schools, and for school teachers and
staff. It introduces examples of seismic retrofitting on nonstructural members that could be identified and
implemented through daily inspections.
With the introduction of the new seismic codes (1981) in the Building Standard, seismic retrofitting of
buildings has made progress. For school facilities, the Ministry of Education, Culture, Sports, Science and
Technology (hereafter called; the Ministry) has established the Guideline for Improving the Seismic Resistance
of School Facilities (July 2003).
At the investigative research cooperator meeting for establishing the Guideline for Improvement of
School Facilities, which was held in March 2005, a proposal was made for the urgent improvement of seismic
resistance in school facilities. It is believed that further measures for improving the seismic performance of
school buildings will proceed in the future.
Through these efforts, damages to the school main structure from earthquakes would be reduced.
However, when retrofitting is insufficient, nonstructural members, such as ceiling material, equipment, and
various fixtures could fall or topple, and could cause significant harm to children and others.
In recent years, people have been harmed by falling nonstructural members from earthquakes, such as from the
Geiyio Earthquake (March 2001), Mid-Niigata Prefecture Earthquake (October 2004) and the Fukuoka
Prefecture West Offshore Earthquake (March 2005). It is still fresh in our memories that many people, who
were inside a sports facility, were hurt from falling ceiling material during the earthquake (Magnitude 7.2,
maximum seismic intensity 6 lower), that occurred in August 16, 2005, with a hypocenter off the coast of
Miyagi Prefecture.
This case study is based on the "Investigative Survey Report on the Seismic Inspection of Nonstructural
Members in School Facilities" (March 2002) (hereafter called the "Academic Report on Nonstructural
Members"), which the Ministry commissioned the Architectural Institute of Japan to develop.
The examples of seismic non-structural retrofitting in school facilities show the conditions of
damages from previous earthquakes, as well as retrofit examples, by using photos and illustrations to make
them easier to understand.
It is our hope that this case study, together with the "Academic Report on Nonstructural Members", will help
increase the awareness among school founders, administrators, teachers and staff, toward the need for seismic
retrofitting of non-structural members as well as toward retrofitting methods. Consequently, it is hoped that
this will contribute in securing the safety of students and children.
2. Definition of Nonstructural Member
"Nonstructural member" refers to members other than major structures that are such as columns, beams, walls
and floors. In the narrow sense, the term indicates portions of structures, such as exterior walls, which are not
major structures, but in the broad sense, this could include items, such as fixtures and furniture.
In this document, nonstructural members include all members and components (nonstructural member in the
broad sense that includes fixtures and furniture), excluding structural members. Such items will be referred to
as "nonstructural members".
Table 1
Classification of members and components that compose structures
Categories
Sub-categories
Main
Items
Specific examples
Major structural item
Column, Horizontal member,
Foundation, Piling
Structure
Main structure
structure
Roof , Column, Beam, Floor,
Stair
Structural
element
Workpiece Specific structure
Secondary member
Chimney (more than 6 m high),
etc.
Precast panel frame
Wing wall,
Others
RC non-bearing wall
Hanging
wall,
Standing wall
Roof,
Portion of structure
Minor
structure
Nonstructural construction Building attachment
element
Non-structural facility
element
Exterior wall,
Ceiling, Interior wall
Billboard,
Chimney (less than 6 m high),
etc.
Exterior items
Wall,
Attachment to main
structure
Expansion joint, etc.
Furniture and fixture
Furniture, Fixture, Ornaments
Equipment
Equipment unit
Pipe and ductwork
Vertical ductwork, Horizontal
ductwork, etc.
Other facilities
Elevator, Escalator
Fence
Non－structural
member
非構造部材
Structural
member
構造部材
Overall
structure
建物全体（構造部材+非構造部材）
(structural + non-structural members)
Only structural
member
構造部材のみ
Figures were excerpt from the "Structural Training Materials" (Architectural Institute of Japan, ed.)
3. Case Studies of Seismic Retrofitting
This document looks into the following 19 cases of 'non-structural members' among school facilities that
are relatively prone to damages from earthquakes. Seismic nonstructural retrofitting of such item is thought to be
possible through daily inspections and at low costs. Then, the conditions of damage and cases of retrofitting will be
shown.
For further information on retrofitting, please refer to related sections of the "Academic Report on
Non-structural Members".
№
Cases of retrofitting
①
Ceiling material
②
Window and windowpane
③
Exterior wall and siding (concrete block and ALC walls)
④
Lighting fixture
⑤
Outdoor unit (air conditioner and heating unit)
⑥
Elevated water tank and cooling tower
⑦
Chimney
⑧
Refrigerator
⑨
Bookshelf and locker
⑩
TV and computer
⑪
Piano
⑫
Machine tool
⑬
Storage shelves in special classes
⑭
Gymnasium equipment and facility
⑮
Shoe locker
⑯
Wall and gate post
⑰
External staircase and surroundings
⑱
Retaining wall
⑲
Other items
Damage Conditions and Retrofitting; Case 1
Ceiling Material
Damages
■Fallen auditorium ceiling
・Auditorium ceiling material fell together with the
mounting brackets because of significant seismic
motion.
■Falling ceiling materials at the special
classroom
・Ceiling boards fell together with the mounting
brackets because of significant seismic motion.
2004 Chuetsu Earthquake, Niigata
1993 Hokkaido Southwest Offshore Earthquake
Retrofitting
Ceilings with even surfaces
Walls and
columns
■ Daily inspection
・Verify that tie braces are installed by inspecting through access
ports.
・Verify that intervals between hanging bolts are sufficient and that
the bolts are tightened.
・Verify that ceiling board have not moved, cracked or deformed,
and that fasteners are not loose or rusted.
■ Retrofitting
・Provide sufficient space between ceiling material and wall or
column.
・Hanging bolts are long (≥1500 mm) in gymnasiums where there
are significant space between the roof and ceiling). Horizontal and
diagonal tie braces should be installed to prevent the ceiling from
moving.
Tie brace
Provide space (gap)
Ceiling surfaces that are uneven or set at different levels
○ Ceiling surfaces set at different levels
・This results in some portions of ceilings with high or low
rigidity, which requires retrofitting, such as by securing space
between portions with different rigidity.
○ Ceiling with irregular horizontal layout
・Ceilings with irregular horizontal layout could be damaged
at the joint between the rectangular portions of ceilings.
Disconnecting the restraint at such joint is effective.
Provide space between
ceiling surfaces that are set
at different levels.
Column
Restraint
Ceiling plan
Disconnect
Possible damage and falling
Direction of movement
beforehand
Space (gap)
Note (Reference)
■ For retrofitting, refer to the "Survey report on ceiling damages at the airport terminal building from the 2003
Tokachi-oki Earthquake", cited in the "Measures against falling ceilings in buildings with large open spaces (Ministry
of Land, Infrastructure and Transport, Oct. 14, 2003)".
◇http://www.nilim.go.jp/japanese/report/journal/tenjou.pdf
Damage Conditions and Retrofitting; Case2
Window and Windowpane
Damages
■Damages attributed to the windowpane installation method
・Fixed windows were damaged, when installed with hard
sealants according to the previous method in use before the
current provision*, and the windowpanes could not follow
structural deformation.
・When wire-reinforced glass is cracked, it does not fall, but
normal sheet glass becomes shattered and fall.
1993 Hokkaido Southwest Offshore Earthquake
(Photo: Nakano Lb., IIS, University of Tokyo (a))
■Derailed windows and doors
・The earthquake impact derailed the fixtures and
broke windowpanes.
1994 Sanriku Offshore Earthquake
(Photo: Nakano Lab., IIS, University of Tokyo)
■Damaged windowpane hit by braces.
・Buckled bracing members at the gymnasium protruded
in the lateral direction, hit the windowpane, and broke
the glass (Photo a).
2004 Chuetsu Earthquake, Niigata
Retrofitting
■Prevent sidings from falling
2004 Chuetsu Earthquake, Niigata
・Apply antishattering film on normal sheet glass,
to make it act like wire-reinforced glass, and
prevent the glass from shattering and falling.
・Inspect that there are no degradation or loosening
of fixtures. Adjust fixtures if necessary.
■Allow deformation of adjacent members
・Stop using hard sealants to fix sheet glass to the
window frame. Install windowpanes in
accordance to the current design provision*.
・Use bracing connections that prevent buckling of
tie braces in the lateral direction (Right photo).
2004 Chuetsu Earthquake, Niigata
Note (Reference)
■For details, refer to the "Measures against earthquakes for windowpanes", Japan Building Disaster Prevention
Association.
◇ http://www.kenchiku-bosai.or.jp/topics/madogarasuNEWS.html
*Design provision: Since Notification No.109, No.3, No.4 of 1978 by the Ministry of Construction, external
curtain walls that are more than three stories high should not use hard sealants to install windowpanes into fixed
windows. However, this could be exempt when wire-reinforced glass or other safety measures are implemented.
Exterior Sidings
(Concrete Block and ALC Walls)
Damage Conditions and Retrofitting; Case 3
Damages
■Collapsed concrete block sidings
■Collapsed ALC* and precast panel sidings
・Staircase roof was directly hit by block sidings that
collapsed from the gymnasium gable wall.
・Exterior sidings was damaged and had fallen, when
they could not follow the seismic deformation, or
when they collided with adjacent structures (main
structures were steel in both cases).
2005 Fukuoka
Prefecture West
Offshore Earthquake
1995 South Hyogo Prefecture Earthquake
(Photo: Nakano Lab., IIS, University of Tokyo)
Internal view of the roof
directly hit by collapsed
block sidings.
Collapsed concrete block
sidings
2004 Chuetsu Earthquake, Niigata
Retrofitting
■Daily inspection
・Verify that exterior sidings have not degraded, such as loosening, uplifting, spalling, or cracking.
・Verify that the shape and dimensions of fasteners (mounting hardware for siding materials) are appropriate.
■Prevent sidings from falling
・Repair spalling and cracked sidings by injecting resin, replacing fasteners, reinforcing to prevent collapse, or
refurbish with other building methods. (If immediate implementation is difficult, apply emergency measures, such as
by restricting entrance or passage by considering the potential area affected by falling material.)
Note (Reference)
■ For refurbishment, refer to the report *1; "Investigative Survey on the Seismic Inspection of Nonstructural Members
in School Facilities".
*ALC panel: Autoclaved lightweight (aerated) concrete panel. The high temperature and high pressured steam cured
'autoclaved aerated lightweight concrete' panel, which is a factory-fabricated building material that is light, fireproof,
and has high insulation performance. The material is frequently used as exterior sidings, and the standard panel size is
about 600 mm wide and 100 mm thick.
Precast concrete panel: A collective term for standardized reinforced concrete panels prefabricated in factories.
The material is used as columns, beams, wall panel, roof panel, etc., that are assembled at site to form structures.
Lighting Fixture
Damage Conditions and Retrofitting; Case
Damages
■Fallen lighting fixture (chain pendant
type)
・Lamps fell to the floor together with
mounting brackets (chain pendant type).
2004 Chuetsu Earthquake, Niigata
■Fallen lighting fixture (pipe hung type)
・Lamps were left dangling when mounting
brackets in the ceiling failed.
2004 Chuetsu Earthquake, Niigata
Retrofitting
■Daily inspection
・Verify that lamp mounting brackets are not loose.
・Verify that there is no rust or deterioration of mounting
brackets.
・Verify that lamp shades are not left loose.
■Retrofitting
・Modify hooks on mounting brackets to those with safety
latches (See figure below).
・By covering lamp chains with commercially available
plastic tubes, the earthquake impact on fixtures could be
reduced.*
・Installing sway braces to pendant lights is effective, and
electrical raceways should be fixed to columns or walls (See
right figure).
Install sway braces
Hanging bolt
Verify that sway braces are
installed
Electrical raceway
Fluorescent lamp
Example of sway brace
Modify hook
Stainless steel wire
Example of mounting an
electrical raceway
Note (Reference)
■ Retrofitting methods above are excerpts from the report *1; "Investigative Survey on the Seismic Inspection of
Nonstructural Members in School Facilities".
■Replacing lamps with 'shatter-resistant fluorescent lamps' is also effective.
*Excerpt from the "Research and development on fall prevention", Fire Research Institute, Tokyo Fire Department.
◇http://www.tfd.metro.tokyo.jp/ts/skk/02-3.htm
Outdoor Unit
(air conditioner and heater)
Damage Conditions and Retrofitting; Case 5
Damages
■ Overturned air conditioner outdoor unit
・The outdoor unit overturned when the mounting
fixture failed during the seismic impact.
■Dangers of placing outdoor units on eaves and
roofs.
・Falling air conditioner outdoor units that are
installed on roofs and balconies could harm
pedestrians.
2005 Fukuoka Prefecture West
Offshore Earthquake
Retrofitting
■Daily inspection
・Verify that there is no rust or deterioration of mounting
fixtures.
・Verify that mounting fixtures are intact and sufficiently
anchored to the base.
■Prevent overturning
・Install restrainer to prevent uplift of outdoor units (See right
photo).
Note (Reference)
■ Sufficient care is needed for installing air conditioner outdoor units on roofs and balconies at
the second floor and above, since they could fall from the seismic impact and harm pedestrians.
Damage Conditions and Retrofitting; Case 6
Elevated Water Tank and Cooling Tower
Damages
■Shifting on concrete base
・Insufficient anchoring of elevated tanks and
cooling towers result in shifting and displacement
from the impact of the seismic motion.
■Shifting and displacement on concrete base.
・Seismic motion shifted the elevated water tank, which fell off
the base.
・The seismic motion shifted and overturned the concrete base
itself.
2004 Chuetsu Earthquake, Niigata
2004 Chuetsu Earthquake, Niigata
Retrofitting
■Daily inspection
・Verify that there is no rust, deterioration or loosening of anchor bolts or uplift restrainers.
・Verify that there are no defects or damages on the concrete base where anchors or uplift restrainers are fixed.
・To continue the use of items from immediately after the earthquake, verify that the pipe connectors use flexible
joints.
Restrainer
Restrainer
変位吸収継手の例
Typical
flexible joint
For a unit with relatively low
center of gravity, a restrainer
that could restrain horizontal
displacements is sufficient.
For units with high center of gravity,
it is advisable to use restrainers
that could restrain horizontal displacement
and uplift.
Concrete base
Prior chipping of floor slab
and applying water when
pouring concrete are needed.
Floor slab
Insert and fix with concrete anchor (obtain
solid connection between rebar and anchor head)
Note (Reference)
■ Countermeasures that are shown are excerpts from the "Disaster Management Manual", Institute of Industrial
Science, University of Tokyo (April 2002).
Damage Conditions and Retrofitting; Case 7
Chimney
Damages
■Damage on reinforced concrete outdoor chimney
■Tilted metal chimney
・Damage at the base of reinforced concrete chimney positioned
above the roof (See photo a)
・Fallen chimneys that had stood along the school building.
・The top of indoor and outdoor metal chimneys
have tilted.
(a)
1983 Japan Sea Earthquake
(Photo: Nakano Lab., IIS, University of Tokyo)
(b)
2004 Chuetsu Earthquake, Niigata
1983 Japan Sea Earthquake
(Photo: Nakano Lab., IIS, University of Tokyo)
2004 Chuetsu Earthquake, Niigata
Retrofitting
■Daily inspection
・For concrete chimneys, verify that there are no degradations, such as cracks, detachment or spalling of surface mortar,
rusting rebars, and deterioration.
・For metal chimneys, verify that there are no rusting or degraded fixing brackets, loose fixing wires, or moving
chimneys.
・Inspect that old or unused chimneys are not left remaining in school.
■Prevent chimneys from overturning and falling
・If possible, remove chimneys that have no plans to be used.
・Install sway brace on chimneys. For heavy concrete chimneys, the fixed end of fixing stay or wire should be
sufficiently bound or anchored.
・Chimneys that are difficult to reinforce should be removed when refurbishing the building. Until then, the chimney
should be reinforced as mentioned before, or for chimneys with small influence areas when they fall, entrance to the
potential influence areas should be restricted.
Note (Reference)
■ For refurbishment, refer to the report *1; "Investigative Survey on the Seismic Inspection of Nonstructural
Members in School Facilities".
Damage Conditions and Retrofitting; Case 8
Kitchen Equipment, such as Refrigerator and Oven
Damages
■Overturned oven
・The seismic motion caused the large kitchen oven
to moved forward, hit the trolley and tilt steeply.
■Overturned refrigerator
・Large kitchen refrigerator fell forward because of
the seismic motion.
2004 Chuetsu Earthquake, Niigata
2004 Mid-Niigata Prefecture Earthquake
Retrofitting
Fixing bracket
■Daily inspection
・Verify that the equipment is fixed to the floor with fixing
brackets at the support base, and the top part is fixed to the
wall.
・Verify that the fixing brackets are not rusted or degraded.
・Verify that fixing brackets are not loose.
・Install equipment on flat surfaces to restrict overturning.
・To store heavy items, store items in low positions to keep
the center of gravity as low as possible.
■Retrofitting
・Equipment that is not fixed to the floor or wall, should be
secured with fixing brackets.
・Fix equipment to the floor with adjustable fixing brackets.
Adjustable fixing
bracket
Fix to the floor slab
Cross section
Refrigerator
Refrigerator
Adjustable fixing
bracket
Anchor bolt
Example of adjustable
fixing bracket
Note
■Seismic retrofitting of kitchen equipment, such as refrigerators, is important to prevent fires being caused by
seismic motion, since fires are being used in the kitchen.
■Retrofitting methods above are excerpts from the report *1; "Investigative Survey on the Seismic Inspection of
Nonstructural Members in School Facilities".
Damage Conditions and Retrofitting; Case 9
Bookshelf and Lockers
Damages
■Prevent overturning of bookshelves and lockers, and
prevent contents from bursting out.
・Overturned bookshelves and lockers by the seismic motion.
The contents burst out and were scattered over the floor.
2004 Chuetsu Earthquake, Niigata
2004 Chuetsu Earthquake, Niigata
Retrofitting
■Fixing and securing bookshelves and lockers
・Fix bookshelves and lockers to sturdy wall, beam or ceiling
with metal brackets.
・Interconnect the top of tall and shallow bookshelves.
・Bookshelves or lockers that are stacked should be fixed at
the base and at the joint.
・Install a latch at the center of front opening doors.
Install latch
to front
opening
doors.
Install front support
on shelves.
2004 Chuetsu Earthquake, Niigata
Note
(Reference)
■ Countermeasures that are shown are excerpt from the "Disaster Management Manual", Institute of
Industrial Science, University of Tokyo (April 2002)
Damage Conditions and Retrofitting; Case 10
TV and Computers
Damage
■TV that fell from the shelf
・TV that was placed on the shelf toppled and fell.
・There were many cases of TV that did not topple, but
skid off the shelf.
・Furthermore, TV and shelves that had toppled blocked
the classroom entrance and became obstacles to
evacuation. (See photo a)
■TV that fell from hanging shelf
・Seismic motions caused the TV to skid off the hanging
shelf. (See photo b)
・TV falling off hanging shelves could cause serious head
injuries.
・Seismic motions caused desktop computers to fall off the
desk.
■Computers that fell (See photo c)
(a) 2004 Chuetsu Earthquake, Niigata
(b) 2004 Chuetsu Earthquake, Niigata
(c) 2004 Chuetsu Earthquake, Niigata
Retrofitting
■TV placed on shelf
・The shelves should be relatively low and stable.
・When TVs are to be placed on relatively high shelves,
the shelves should be prevented from overturning (See
Case 9; bookshelves and locker).
・The TV should be sufficiently fixed to the shelf with
belts or other means to prevent it from skidding and
falling (See photo d and e)
・It is important to verify that hanging shelves are
sufficiently anchored to the concrete slab above the ceiling
board.
■Computer
・To prevent desktop computers and displays from
overturning, it is effective to secure their movement by
using tie-down straps and self-adhesive cushion pad
(Photo f).
■TV placed on hanging shelves
・Verify that the mounting brackets of hanging shelves are
secure and not loose.
・The TV should be securely fixed to the shelf with belts
or other means to prevent it from skidding off (See
Example of tie-down strap
photo d and e)
(d)
(e)
(f)
Note (Reference)
■ TV stands on wheels could move significantly. Therefore, such TV stands should be fixed to prevent moving or
overturning.
■ Many commercially available TV stands could be fixed at the back. In such cases, they should always be fixed.
Damage Conditions and Retrofitting; Case 11
Piano
Damages
■Skidding grand piano
・The grand piano side slipped from the seismic motion.
・In this case, the wheel restrainer and the piano slipped
together, and therefore, the movement was not significant.
However, if the wheel restrainer failed, the piano could have
slipped far greater distances.
2004 Mid-Niigata Prefecture Earthquake
Retrofitting
■Grand piano
・The wheel restrainer of the grand piano was effective in
restraining horizontal movement. However, large seismic
motions accompanied by vertical movement could derail
the wheels.
・To prevent the piano wheels from derailing, deeper seismic
restrainers are more effective (See finger a).
・ It is also effective to install a support frame (custom
made) to prevent the grand piano from overturning (See
photo b).
■Upright piano
・Upright pianos are set with their backs against the wall.
・Fix the piano on a board to increase the area of the base
to prevent overturning (Photo c and d).
Roller wheel
Rubber seismic restrainer
(a)
(b)
Cross
Section
(c)
(d)
ピアノを板の上に固定
Fix upright
piano on to a board.
Note (Reference)
・It is also advisable to inspect the conditions of instruments other than the piano.
Damage Conditions and Retrofitting; Case 12
Machine Tools
Damages
■Overturned machine tools
・Large machine tools used for training in a technical
high school side slipped from the base and was
overturned by the seismic motion.
・Machine tools were often not fixed to the floor and
consequently sustained damages.
2004 Chuetsu Earthquake, Niigata
Retrofitting
■Prevent machine tools from overturning
・Fix machine tools to the floor according to the
manufacturer's specification (Photo a).
・When it is difficult to fix to the floor, increasing the
base area, such as by using steel plates, is effective in
preventing the machine from overturning (Photo b).
・ Machine tools with relatively high center of gravity
are prone to overturning, and therefore, the machine
and its support frame (including the desk) should be
fixed to the floor. Inspect that the mounting
brackets are intact and not loose (Photos c and d).
(a)
(c)
(b)
(d)
Note (Reference)
■ When machine tools are renewed, old tools are often left at the training room corner or in corridors without
being fixed. Large machine tools that are not in used should be discarded.
■ If they have to be temporarily left, they should be set in places with few passers-by and should be restrained,
such as with ropes, to prevent overturning.
Damage Conditions and Retrofitting; Case 13
Storage Shelves in Special Classrooms
Damages
■Overturned dishes (Home economics
classroom)
・The seismic motion opened the front doors of
storage shelves and the dishes fell to the floor.
■Overturned lab equipment (Science classroom)
・The seismic motion opened the front doors of
storage shelves, and the contents fell to the floor,
destroying the lab equipment.
2004 Chuetsu Earthquake, Niigata
2004 Chuetsu Earthquake, Niigata
■Retrofitting
Retrofitting
・Using antishattering films on glass shelf doors is
effective.
・Organize the contents of storage shelves.
・Install latches on shelf doors to prevent them from opening.
・Do not place heavy objects on upper shelves.
Support unstable equipment, such as by embedding in sand
・Verify that the front latches of storage shelves are not
box or in divided containers to prevent overturning.
loose or rusted.
・Install support bars to the front of shelves to prevent
contents from side slipping.
Install
latch at
Spread soft liner
Prevent overturning, such
the center
sheets on shelves
as by fixing with wired.
to prevent the
of shelf
contents from side
doors.
■Daily inspection
slipping.
Support unstable
equipment, such as
by embedding in sand
box or in divided
containers to prevent
overturning.
Replace glass
containers with
plastic ones as
much as possible
Secure glass shelf doors
with antishattering films.
Install support bar on
shelves to prevent
contents from side
slipping.
Prevent shelves from overturning
It is advisable to install
latches at the top and
bottom of shelf doors.
For only one latch,
install at the center of the
shelf door.
Positions of latches.
Note (Reference)
■Retrofitting methods above are excerpts from the report*1; "Investigative Survey on the Seismic Inspection of
Nonstructural Members in School Facilities".
Damage Conditions and Retrofitting; Case 14
Gymnasium Equipment and Facilities
Damages
■Overturned and damaged basketball goal
・Seismic impact broke the support of the basketball
goal and it fell to the floor.
■Fallen gymnasium lights
・Many HID (high intensity discharge) lamps
installed at the gymnasium ceiling have fallen.
2004 Chuetsu Earthquake, Niigata
■Fallen loudspeaker
・Loudspeaker that was set by the wall, fell from
the support frame onto the floor.
2003 North Miyagi
Prefecture Earthquake
2001 Geiyo Earthquake
Case Study
■Daily inspection
Basketball goalpost, loudspeakers, etc.
・Verify that the mounting brackets and bolts are not
loose or damaged.
・Verify that there is no rust or deterioration on
mounting brackets.
Gymnasium lighting fixtures
・Verify that the mounting brackets of hanging lamps
are not rusted.
・For arena lighting fixtures, verify the safety of
mounting brackets for the hoist mechanism.
■Retrofitting
・Falling heavy objects, such as loudspeakers, could
cause considerable damage. Therefore, these have to
be securely fixed to the wall in at least two positions, at
the top and bottom of the loudspeaker.
Note (Reference)
■The retrofitting above are excepts from the report *1; "Investigative Survey on the Seismic Inspection of
Nonstructural Members in School Facilities".
Damage Conditions and Retrofitting; Case 15
Shoe Locker
Damages
■Overturned shoe locker
・The student shoe lockers at the entrance, which were
set back-to-back, were overturned like dominos by the
seismic motion.
・Overturned shoe lockers could block the evacuation
route and obstruct evacuation after the earthquake.
2003 Tokachi-oki Earthquake
Retrofitting
■Securely fix shoe lockers near the student entrance to the wall, such as
with support wires (Figure a).
・Shoe lockers that are not always set along the wall, such as those standing
at the entrance. These should be fixed to the strong part of the ceiling or
the beam with metal brackets (Figure b).
■Damaged aquarium
・When items set near the entrance, such as aquariums, topple and break,
they could obstruct evacuation. Therefore, the support frame should be
fixed with metal brackets. At the same time, to prevent the aquarium from
side slipping, it should be fixed with support or wire, together with selfadhesive cushion sheets.
・When it is difficult to apply such measures, items that could obstruct
evacuation should not be placed.
Shoe locker
(b)
Prevented overturning by
countermeasures
2005 Fukuoka Prefecture
West Offshore Earthquake
Wall
Rope retainer hook
Restrainer
hook
Overturned and
broken aquarium
Rope or wire
(a)
Note (Reference)
■ Illustrations of countermeasures that are shown are excerpt from the "Disaster Management Manual", Institute of
Industrial Science, University of Tokyo (April 2002)
Damage Conditions and Retrofitting; Case 16
Wall and Gatepost
Damages
■Overturned or collapsed wall
・Stone and concrete block walls were toppled and
collapsed by strong seismic motions. Toppled or
collapsed walls are frequently reported in other
regions as well.
■Tilted, toppled or rotated gatepost.
・Gatepost that tilted by ground deformation in a school
that stood on sloping ground.
・On grounds that are not sloped, there were cases of
gateposts that rotated at the base and those that have
tilted or toppled because of liquefaction.
2005 Fukuoka Prefecture West
2004 Chuetsu Earthquake, Niigata
Offshore Earthquake
1978 Miyagi-oki Earthquake
Retrofitting
■Daily inspection
・Verify that the walls are not shaky, tilted, or unnecessarily high.
・Verify that the concrete block, masonry joint and steel rebars have not degraded or rusted.
・Verify that wall foundations are sufficiently embedded, and that the intervals between steel rebars, buttresses and
stay posts are also sufficient.
・Verify that the heights of concrete block walls were not increased.
■Prevent overturning.
・Walls that are potentially dangerous should be
rebuilt, or replaced with light fences, such as
hedges or wire fence.
・Reinforce with buttresses or steel support frames
(See right photo).
1997 Northwest Kagoshima Prefecture Earthquake
(Photo: Nakano Lab., IIS, University of Tokyo)
Note (Reference)
■ Concrete block walls are specified in Item 8, Article 62 of the Building Standards.
■ For inspection and retrofitting of concrete block walls, refer to the pamphlet "Effort for building safe concrete
block walls" (Subcommittee on concrete block wall systems, Working committee on masonry wall construction,
Construction material committee of the Architectural Institute of Japan), which gives detailed information.
◇http://news-sv.aij.or.jp/zairyou/s2/index.html
◇http://news-sv.aij.or.jp/zairyou/s2/pamphlet.PDF
Damage Conditions and Retrofitting; Case 17
External Staircase and Surroundings
Damages
■Tilted steel external staircase
・The steel external staircase tilted from the
foundation.
■Tilted reinforced concrete wall of the external staircase
・The exterior wall of the staircase was damaged and tilted
outward.
・There are risks that these could collapse and fall from the
aftershock.
1987 Chiba Prefecture East Offshore Earthquake
2004 Mid-Niigata Prefecture Earthquake
(Photo: Nakano Lab., IIS, University of Tokyo)
■Tilted reinforced concrete wall of a staircase
・The staircase wall of a gymnasium, which was
built on a sloped ground, was damaged and
became tilted.
・This appears to be caused by the effect of cracks
at the staircase floor from ground deformation.
Heavy reinforced concrete walls could easily tilt
or topple, once they are damaged by seismic
motions (See right photo).
2005 Fukuoka Prefecture West Offshore Earthquake
Retrofitting
■Daily inspection
・Inspect and verify that the staircase is sufficiently and solidly joint to the structural frame, and that the staircase is
structurally sufficient to support itself. The inspection and verification should be performed together with the
seismic evaluation of school buildings and gymnasiums.
・Verify that staircases are not shaky and that the anchor bolts have not degraded. It should be noted that, walls that
protrude or placed far from floor slabs or staircases, or walls that have no support members are prone to seismic
motions.
■Retrofitting
・When cracks occur on staircases and walls, or when they tilt after earthquakes, they are at risk of overturning or
falling. Therefore, these facilities should be prevented from being used, and considering their effects, entrance to
nearby areas should be restricted.
Damage Conditions and Retrofitting; Case 18
Retaining Wall
Damages
■Damages on retaining wall
・Significant damage to retaining walls, such as the settlement of surrounding grounds, buckling or cracking
that accompanies ground deformation on sloped or developed grounds have occurred frequently (Photo a).
・Shifting of retaining walls, even those that are relatively new, have been observed (Photo b).
2004 Chuetsu Earthquake,
Niigata(Photo: Nakano Lab., IIS,
University of Tokyo)
(a)
■School ground that collapsed together with the
cliff
・School ground, which stands on sloping ground
that collapsed with deformation of the ground.
2005 Fukuoka Prefecture West Offshore Earthquake
(b)
1995 South Hyogo Prefecture Earthquake
(Photo: Nakano Lab., IIS, University of
Tokyo)
■School commuting route that was affected by the
slope failure.
・The school commuting route was blocked as the slope
in the mountainous region failed.
2005 Fukuoka Prefecture West Offshore Earthquake
Retrofitting
■Daily inspection
・Verify that there are no cracks or buckling of retaining wall
・When the building stands directly above or below a steep slope, and when people or vehicles travel such areas, the
safety of the ground and retaining walls against earthquakes should be studied by an expert.
■Retrofitting
・When cracks or shifting of retaining walls are confirmed after an earthquake, the fact that the retaining walls are at
risk of failing or tumbling should be clearly indicated at inside and outside the school. It is necessary to restrict
passers-by immediately, and notify the danger to students and public who may pass near the retaining wall.
Other Items
Damage Conditions and Retrofitting; Case 19
Damages
■Overturned monuments
・Monuments and statues in the school ground were
overturned by earthquakes.
・There was a case in the past, where a stone lantern in
a shrine was overturned and caused casualty. (1987
Chiba Prefecture Eastern Offshore Earthquake)
2004 Chuetsu Earthquake,
Niigata
1987 Chiba Prefecture
Eastern Offshore
Earthquake
■Overturned snow fence material
・Timber for snow fences that were propped up against
the school building have toppled.
・Those that had been restrained by wires did not topple
significantly.
2004 Chuetsu Earthquake, Niigata
Retrofitting
■Daily inspection
・Inspect inside and outside of buildings to see that there are no timber and long or wide stone plaques propped up
against the building wall.
・Verify that monuments are not shaky and that their foundations are sufficiently embedded.
■Prevent overturning.
・Implement measures to prevent timber and other material from collapsing. Then, they should be either piled flat,
or restrained from toppling with wire, chain or rope.
・Verify that the restraining wire, chain and rope are of sufficient length (or height) and strength, considering the
weight of the material. Then, the materials should not be tied loose and restrained by giving sufficient
consideration to the lengths of the material.
・Heavy objects such as stone plaque or monuments
should have their foundations sufficiently
embedded or sufficiently reinforced to prevent
them from toppling at the base.
* If immediate implementation is not possible, apply
emergency measures, such as by restricting
entrance or passing the surrounding areas.
1978 Miyagi-oki Earthquake (Photo: Nakano Lab., IIS,
University of Tokyo)
Note (Reference)
■To prevent toppling, refer to the report *1; "Investigative Survey on the Seismic Inspection of Nonstructural Members
in School Facilities".